Located in the southwestern part of Himachal Pradesh, Una sits on the border of the Hoshiarpur and Rupnagar districts of Punjab. The geography of the city and its surrounding district is largely defined by the Shivalik range of the Himalayas, featuring low hills and expansive, relatively flat valleys.
The most defining geographical and hydrological feature of the region is the Swan River, which bisects the Una district. Historically referred to as the "River of Sorrow" due to its devastating monsoon floods, modern channelization projects have stabilized the riverbanks, reclaiming vast tracts of land for agriculture and urban development. The region features a mix of deciduous forests, scrublands, and cultivated plains.